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| author | Ben Blum <bblum@andrew.cmu.edu> | 2011-11-02 13:38:07 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-11-02 16:06:59 -0700 |
| commit | 77ceab8ea590d7dc6c8f055ce43dfebd74428107 (patch) | |
| tree | b2ef5e5baca4579565ab9bf527e965dd9b93a25a /kernel | |
| parent | 33ef6b6984403a688189317ef46bb3caab3b70e0 (diff) | |
| download | blackbird-obmc-linux-77ceab8ea590d7dc6c8f055ce43dfebd74428107.tar.gz blackbird-obmc-linux-77ceab8ea590d7dc6c8f055ce43dfebd74428107.zip | |
cgroups: don't attach task to subsystem if migration failed
If a task has exited to the point it has called cgroup_exit() already,
then we can't migrate it to another cgroup anymore.
This can happen when we are attaching a task to a new cgroup between the
call to ->can_attach_task() on subsystems and the migration that is
eventually tried in cgroup_task_migrate().
In this case cgroup_task_migrate() returns -ESRCH and we don't want to
attach the task to the subsystems because the attachment to the new cgroup
itself failed.
Fix this by only calling ->attach_task() on the subsystems if the cgroup
migration succeeded.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 64b0e73402df..8386b21224ef 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2135,14 +2135,17 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) oldcgrp = task_cgroup_from_root(tsk, root); if (cgrp == oldcgrp) continue; - /* attach each task to each subsystem */ - for_each_subsys(root, ss) { - if (ss->attach_task) - ss->attach_task(cgrp, tsk); - } /* if the thread is PF_EXITING, it can just get skipped. */ retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, true); - BUG_ON(retval != 0 && retval != -ESRCH); + if (retval == 0) { + /* attach each task to each subsystem */ + for_each_subsys(root, ss) { + if (ss->attach_task) + ss->attach_task(cgrp, tsk); + } + } else { + BUG_ON(retval != -ESRCH); + } } /* nothing is sensitive to fork() after this point. */ |
